JPH0441400A - Balance valve of balanced cargo controller - Google Patents

Abstract

PURPOSE:To obtain a stabilized and balanced state without any leak of work oil by using an elastic film on both sides of the spool of a balance valve for oil pressure adjustment on a balanced cargo controller which is able to keep a balanced state for the cargoes of optional weights. CONSTITUTION:The inside spool of the housing 1d of a balance valve is equipped in the state capable of sliding so as to balance the inside pressures of a chamber 11 and a chamber 12 by a slot 2C. Also, elastic films 5, 6 are fixed by being sandwiched between both end covers 3, 4 of the housing 1d. When the worker lifts a cargo 52, a pressure in the chamber 51a of an actuator 51 is dropped, and a pressure of a chamber 13 connected thereto is dropped, as well. As a pressure on the side of a chamber 14 acts on the film 6 and the spool 2 moves toward left in the drawing, a port 1b is opened, and the pressurized oil from an oil pressure source 53 is sent into the chamber 51a of the actuator 51 to lift the cargo 52. When releasing the cargo 52, the chamber 13 and the chamber 14 are balanced each other again, and the cargo 52 is stopped. Thus, since the films 5, 6 intercept the chamber 13, from the chamber 11 and the chamber 12, from the chamber 14, there happens no break of a balance caused by leakage.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a load balancing device, and more particularly to a balance valve for a balancing load handling device.

[Conventional technology]

FIG. 2 is a circuit configuration diagram showing a conventional technique in a balancing cargo handling device. In FIG. 2, 51 is an actuator;
1c is a piston of the actuator 51, 51d is a piston rod, and 51c and 51d are fixed together. 5
2 is a load, which is lifted or attracted by a piston rod 51d. 53 is a hydraulic power source, 54 is a relief valve, 5
6 is a manually operated valve, 57 is a weight memory valve, and 58 is a balance valve. The operating valve 56 is manually switched so that the load 52
This is a valve that raises and lowers the 56c position.
The zero weight memory valve 57, which opens downward at position a, is in manual mode at position 57a, and in balance mode at position 57c. In the balance valve 58, when the weight memory valve 57 is in the balance mode 57c position and the operating valve 56 is in the 56b position, the pressure of the accumulated pressure 559 acts on the boat 58e and is generated in the chamber 51a of the actuator 51 by the load 52. The pressure acts on the port 58a of the balance valve 58, causing the balance valve 58 to stop at the position 58b, so that the load 52 is stopped at the position. FIG. 3 is a sectional view showing the conventional structure of the balance valve 58, where 58f is a housing, 58g
is slidably mounted in the housing 58f by a spool, and springs 58h are fitted on both sides of the spring 58h to close the ports 64a and 70a, so that pressure from the chamber 51a of the actuator 51 acts from the port 73a. This prevents leakage into the pipes 64 and 70. When the worker tries to lift the load 52 by hand, the actuator 5
The pressure in the chamber 51a of the actuator 51 decreases a little, and therefore the pressure on the port 58d side of the balance valve decreases, so the spool 58g in the balance valve 58 moves and pressure oil from the hydraulic source 53 is sent into the chamber 51a of the actuator 51. If the movement of the load 52 is stopped at that point, the balance valve 58
The pressure acting on port 58d also increases and
When the pressure on the side is balanced, the spool 58g returns to its original position and closes the ports 64a and 70a.

[Problem to be solved by the invention]

Second. As can be seen in FIG. 3, when the weight memory valve 57 is in the position 57c, the housing 58f of the balance valve 58
Since there is a slight gap between the sliding part between the spool 58g and the pilot port 58e, the pilot pressure coming to the pilot port 58e leaks from the port 70a and the pressure decreases, so the spool 58g moves to the right in FIG. The hydraulic oil 73a flows from the port 70a to the tank 55d, causing the load 52 to fall out of balance. Also, when the pressure oil from the pump 53 leaks from the port 64a and the pressure on the boat 58d side increases, the spool 5Bg similarly moves to the right in the figure and loses its balance.
will go down.

The present invention aims to provide a balance valve that will not cause the balance valve 58 to lose its balance due to these leaks.

[Means for resolving divisions and companies]

In order to achieve the above object, the invention of a balance valve for a balanced cargo handling device according to the present invention includes an actuator for raising and lowering a load, a hydraulic source for driving the actuator, and an operation for manually operating the actuator. A balance valve that adjusts the pressure so that the weight of the load and the force generated by the actuator are balanced, and a weight memory valve that switches between manual mode and balance mode to maintain a balanced state for a load of any weight. The balanced cargo handling device to be obtained has a structure in which elastic membranes are used on both sides of the spool of the balance valve.

[For production]

The spool r4rIJ in the balance valve is provided with an elastic membrane to prevent leakage between the port 70a and the pilot port 58e and between the port 64a and the port 58d. Hydraulic oil is blocked by an elastic membrane between the bow) 70a and the pilot port 58e, or between the port 64a and the bow) 58d, so that no leakage occurs (therefore, there is no loss of balance due to leakage, and There will be no more unloading.

〔Example] Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a balance valve of a balanced cargo handling device according to the present invention. 1d is a housing.

2 is the spool, 2a and 2b are the housing, and 1d is the spool.
is slidably mounted inside the. 2C is the pore and chamber 1
The internal pressures of chambers 11 and 12 are balanced through chambers 1 and 12. 5 and 6 are elastic membranes whose peripheries are sandwiched and fixed between the end covers 3.4 of the housing 1d. 1a, 1
b1c is a port provided in the housing 1d;
As shown in FIG. 2, port 1a communicates with the weight memory valve 57 through a pipe 73, port 2a communicates with the pump 53 through a pipe 64, and port 1c communicates with the tank 55d through a pipe 70. Also,
3a is a port provided in I3, which is connected to piping 7 by piping 71.
It is connected to 3. Furthermore, 4a is a port provided in I4 and communicates with the weight memory valve 57 and others through a pipe 69.

Now, when the weight memory valve 57 is in the position 57c (in balance mode), as described above, the port 3a and the bow) 4
The pressure applied to a is balanced and the load 52 is stopped, but when the worker lifts the load 52, the pressure in the chamber 51a of the actuator 51 decreases, and the pressure in the chamber 13 connected via the piping 71 also decreases. Go down. When the pressure in chamber 13 decreases,
The pressure on the chamber 14 side acts on the membrane 6 and pushes the spring 8, so the spool 2 moves to the left in the figure, so the port 1b opens and the pressurized oil from the hydraulic source 53 flows from the port la to the weight memory valve 5.
7 and into the chamber 51a of the actuator 51, the load 52 rises. At this time, pressurized oil is simultaneously supplied to port 3.
Since it is also guided by a, when the hand is released from the load 52, the chambers 13 and 14 are balanced again, the spool 2 returns to the right, blocks the port 1b, and the load 52 stops.

When the operator pushes down the load 52, the pressure in the chamber 51a of the actuator 51 increases, and this pressure acts on the membrane 5 in the chamber 13, moving the spool 2 to the right in the figure, opening the port 1c and opening the port 1c. ) Hydraulic oil from 1a to port 1c
The escaped cargo 52 descends into the tank 55d through the tank 55d. Load 52
When the hand is released, the pressure in the chamber 13 also decreases, the spool 2 returns to its original state and balances, and the load 52 stops.

In this way, membranes 5, 6 are connected to chambers 13 and 11 and chambers 12 and 1.
4 is shut off, there is no leakage as in the conventional technology, and there is no loss of balance due to leakage.

〔Effect of the invention〕

Since the present invention is constructed as described above, there is no loss of balance, so a very stable balanced state can be obtained, and its practical value is extremely high.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a balance valve of a balanced cargo handling device according to the present invention. FIG. 2 is a circuit diagram of the load balancing device. FIG. 3 is a sectional view showing a conventional balance valve. 1...Balance valve 2...Spool 5...Membrane 6...Membrane...Actiator/Load...Hydraulic pump...Operation valve...Weight memory valve

Claims (1)

[Claims] An actuator for raising and lowering a load, a hydraulic source for driving the actuator, an operating valve for manually operating the actuator, and a balance valve for adjusting pressure so that the weight of the load and the force generated by the actuator are balanced. and a weight memory valve that switches between manual mode and balance mode, which is capable of maintaining a balanced state for a load of any weight, in which elastic membranes are used on both sides of the spool of the balance valve. A balance valve for a balanced cargo handling device featuring: